The present invention generally relates to ozone systems and methods and more specifically relates to such systems and methods for agricultural applications, for example for treating living grapevines in vineyards.
Ozone exists as an unstable blue gas. It has been found to be an effective oxidizing agent, and has been used for the purification of drinking water, in industrial waste treatment, for deodorizing air and sewage gases, as a bleach for waxes, oils and textiles, and as an oxidizing agent in chemical processes. Furthermore, in sufficient concentrations, ozone is known to destroy bacteria, fungi, viruses and other microorganisms. Various devices and processes have been developed for disinfecting air and surfaces using ozone gas or ozonated water.
Ozonated water can be used for sanitizing surfaces without heat treatment and without the use of potentially harmful chemicals. This is of particular interest in the development of processes using ozone for treating the surfaces of food products. Unlike other rinse agents, an ozone/aqueous rinse does not leave behind a residue that later needs to be removed from the food product surface.
Not surprisingly, therefor, various methods and systems for treating food products using the known antimicrobial properties of ozone have been developed. More recently, processes using ozone for the treatment of living, agricultural crops have been proposed.
Typically, treatment of crops using ozonated water is accomplished as follows. A stationary water station is provided, for example a stationary tank having a 500 gallon capacity. Ozone gas is introduced into the water tank to form an ozone water mixture in the tank. A tractor or other vehicle is filled with a portion of this ozone water mixture, which is then transported and sprayed onto agricultural crops to treat diseases and pests, such as unwanted or harmful microorganisms.
Smith, Jr. et al U.S. Pat. No. 5,816,498, the disclosure of which is incorporated herein in its entirety by this specific reference, discloses an ozone spray system and method for treating bacteria or fungi on agricultural crops, namely a crop of growing Vidalia onions. The Smith Jr. et al system is an agricultural field and crop sprayer that produces and applies ozonated water to such an agricultural crop. According to Smith Jr. et al, ozonated water is produced by recirculating water to a tank initially containing water free of ozone. The water from the tank is passed through a venturi injector connected to an ozone generator, and then back into the tank until a desired ozone concentration is reached in the tank. A vehicle, for example a tractor driven vehicle, is used to transport a portion of the ozone water mixture through a field of agricultural crops. Ozonated water is sprayed from the tank and onto the crops.
One drawback of the Smith Jr. et al system, as well as other similar systems, is that ozone concentration in the water tank is increased incrementally and gradually as the water is recirculated continuously through an ozone injector, until the desired concentration is reached. Thus, the Smith Jr. et al system therefor requires careful monitoring of the ozone level in the tank, as well as a relatively long waiting period before an effective concentration is reached.
Entire vineyards of grapevines have been seriously damaged or destroyed by the rapid spread of microbial infestations on the growing plants. Generally, these organisms take up residency in the woody stock of a vine and spread to the foliage throughout the growing season, ultimately damaging the berries and contaminating the juice. Such damage/destruction has substantial adverse economical impact, for example, on the wine industry.
It would be advantageous to provide new systems and methods which address one or more of these concerns, for example, while treating agricultural crops, such as living and/or growing grapevines in vineyards.
New ozone systems and methods for agricultural applications have been discovered. The present invention provides safe and effective systems and methods of ozone treatment for agricultural applications which address one or more of the above-noted and other problems. The present ozone systems and methods are highly effective in the treatment of agricultural crops, particularly in the treatment of grapevines in vineyards for control of mildew, other fungi and other microorganism-based infestations. The present systems are straightforward in construction and use. The present methods are easy to practice and provide effective treatments with no significant detrimental effect on the crop or crops being treated.
The agricultural crop treated using the systems and methods of the invention may comprise an agricultural crop selected from the group of crops consisting of leafy vegetable crops, cole crops, legume crops, annual fruit crops and perennial fruit crops. Some embodiments of the invention have been found to be particularly useful for treating and maintaining the health of row crops, for example leafy, relatively low growing row crops, such as crops that are generally less than about two feet in height above a ground level, or less than about one foot in height above a ground level.
An ozone system for agricultural applications, in accordance with the present invention, generally comprises a portable unit that functions to combine a stream or flow of water, preferably substantially free of ozone, with ozone, preferably produced from oxygen-enriched air, to create an ozonated water stream which, substantially directly after being formed, is used to treat agricultural crops, such as plants, fruit on plants, foliage on plants, grapevines and the like. Unlike earlier systems using ozonated water to treat plant diseases, the present invention uses an ozonated water stream formed by a single pass stream of water through an ozone injector, dispensed or applied substantially directly after formation to the crops, preferably employing a spray assist assembly which advantageously provides a high volume, low pressure gaseous component to assist the dispensing of the ozonated water stream.
Moreover, unlike other ozonated water spray systems, the present systems preferably are designed as self-contained, preferably portable, units. The systems include a fluid passageway having an inlet for receiving a flow of water, for example, from a water source. An ozone generator is included. Preferably, ozone is generated using a corona discharge ozone generator for producing a gaseous stream comprising a high concentration of ozone from oxygen, an oxygen-enriched gaseous stream or air. Preferably, the corona discharge generator is adapted to generate ozone in quantities of between about 5 and about 30 grams per hour, and at a concentration of between about 1% and about 5% by weight of the ozone-containing gaseous stream. The ozone preferably is generated directly from an oxygen-enriched gaseous stream, e.g., produced by an oxygen concentrator assembly, for example, of conventional design, or air. The ozone from the gaseous stream is introduced into the water stream or flow by any suitable means, for example, using a venturi injector or like injection assembly. The venturi injector provides a source of suction which urges the ozone-containing gaseous stream from the ozone generator into the water stream or flow. The water is passed through the venturi injector only once prior to dispensing the ozonated water onto the crops through an outlet assembly connected to the fluid passageway. A spray assist assembly preferably is included, as described elsewhere herein, to assist in dispensing the ozonated water for agricultural application.
Optionally, the present ozone systems may include one or more of several subsystems, such as a degassing assembly, hereinafter sometimes also referred to as a degas/separator assembly, for removing undissolved ozone gas from the ozonated water stream, and an ozone destruct assembly in communication with the degassing assembly, for destructing the undissolved ozone gas, and preferably venting the product of ozone destruction, preferably oxygen, into the atmosphere. To ensure effective destruction of ozone gas, a two step process is preferably employed in the destruct assembly. Thus, the undissolved ozone gas stream preferably is both heated and thereafter passed through a catalytic chamber to provide for enhanced ozone destruction.
One or more components of the present systems, such as the oxygen concentration assemblies, the ozone generators, the ozone injection assemblies and the spray assist assemblies, preferably all of such system components, are sized and adapted to be mountable, directly or indirectly, to a motorized vehicle for transporting during operation thereof. Using such a motorized vehicle allows the present systems to be used effectively in relatively large crop fields, e.g., vineyards. The xe2x80x9cone-thruxe2x80x9d ozone generation feature of the present systems also enhances the ability of the present systems to treat relatively large fields.
In addition, in one advantageous embodiment of the invention, a pressure regulating subsystem is provided for maintaining a consistent, regulated internal pressure of the aqueous stream as the stream is processed within the unit or system. The pressure regulating subsystem preferably includes a plurality of, for example three, pressure regulator valves for controlling pressure in various parts of the unit, both upstream and downstream of the venturi injector. In this embodiment, the system is adapted to receive a flow of water from any suitable water source, for example, a municipal water supply, which may have different pressures at different locations, a water reservoir, a stationary water tank, or a transportable water tank mounted to a motorized vehicle. Advantageously, the system is adapted to meet different, varied parameters that are customer or user specific, for example, water reservoir pump capacity. Because the system is a xe2x80x9conce throughxe2x80x9d or single pass ozone generation system, there is no recirculation of ozonated water back to the water source, for example, the water tank. Therefore, the volume of water in the tank or other water source may fluctuate as the source is emptied and refilled, without affecting the concentration of ozone in the ozonated water being applied to the crops.
In addition, initial water pressure to the system may be provided by a pump assembly which is powered by a motorized vehicle on which the remainder of the system is mounted and/or transported during operation, for example, in a crop field, e.g., vineyard. Thus, for example, while the tractor is pulling the system between rows of crops at a substantially constant speed, constant incoming water pressure is being supplied by the pump, thus enabling consistent dispensing of the ozonated water to the crops.
In another broad aspect of the present invention, methods for treating an agricultural crop are provided. Such methods, in general, comprise:
providing a flow of water;
generating a gaseous stream containing ozone;
introducing the ozone from the gaseous stream into the flow of water to form an ozonated water stream;
combining the ozonated water stream with a flowing gaseous component, preferably comprising air, to produce a mixed gaseous component/ozonated water stream; and
dispensing the mixed gaseous component/ozonated water stream to an agricultural crop.
In a different aspect of the invention, a method for treating an agricultural crop is provided, the method comprising the steps of providing a flow of substantially ozone-free water; generating an ozone-containing gaseous stream; forming a substantially continuously flowing ozonated water stream by introducing the gaseous stream into the flow of substantially ozone-free water; and directly applying the ozonated water stream to at least a portion of an agricultural crop; the steps of generating, forming and directly applying being performed by means of a transportable water processing system.
The step of forming preferably comprises forming an ozonated water stream having an ozone concentration of at least about 0.5 ppm to about 2.5 ppm.
In another aspect of the invention, the agricultural crop is an agricultural crop selected from the group of agricultural crops consisting of leafy vegetable crops, cole crops, legume crops, annual fruit crops, and perennial fruit crops, and the dissolved ozone concentration is selected based, at least in part, upon the type of crop being treated.
For example, in some embodiments of the invention, the agricultural crop is a leafy vegetable crop, for example a crop of lettuce plants. In this case, it has been discovered that the step of forming preferably comprises forming an ozonated water stream having a dissolved ozone concentration of at least about 1.0 ppm, and more preferably having a dissolved ozone concentration of at least about 1.5 ppm.
In other embodiments of the invention, the agricultural crop being treated is a low growing, leafy plant bearing delicate fruits, for example a crop of strawberry plants. In this case, it has been discovered that the step of forming preferably comprises forming an ozonated water stream having a dissolved ozone concentration of no greater than about 1.0 ppm, in order to treat the plant without causing damage to the delicate fruit, which may occur upon application of higher concentrations of dissolved ozone.
Preferably, for the treatment of open, leafy, low growing row crops, the step of directly applying comprises applying the stream of ozonated water as droplets of ozonated water, for example onto leafy portions of the crop, in lieu of applying the stream of ozonated water with the assistance of a high pressure and/or blower assisted sprayer.
For example, the step of directly applying comprises applying the stream of ozonated water from a liquid nozzle.
The present systems, as described elsewhere herein, may be employed in practicing the present methods.
In one very useful embodiment, the present methods further comprise transporting the ozonated water stream on a motorized vehicle prior to the dispensing step. In some embodiments of the invention, the method comprises the step of transporting the water processing system, intact (that is, without prior disassembly and/or later reassembly of the system) to another portion, for example another row, of the agricultural crop, and then repeating the steps of generating ozone gas, forming an ozonated water stream, and directly applying the ozonated water stream to the plants.
Although the present methods may be used to treat any suitable agricultural crop, such methods are particularly useful to treat living grapevines in vineyards. Such treatment methods have been found to be very effective in controlling/managing/preventing microbial infestations on grapevines while having no significant detrimental effect on the grapevines, on the foliage or on the fruit or wine produced therefrom. In addition, such methods are environmentally friendly and do not present any significant health risks to the humans practicing the methods or who are otherwise in the vineyards.
Each and every feature described herein, and each and every combination of two or more of such features, is included within the scope of the present invention provided that the features included in such combinations are not mutually inconsistent.